Without limiting the scope of the invention, its background is described in connection with disorders of the skin and, more particularly, to the general field of diseases that cause psoriasis, as an example.
Psoriasis is a common skin disease characterized by hyperplasia of keratinocytes resulting in thickening of the epidermis and the presence of red scaly plaques. The lesions in this chronic disease typically are subject to remissions and exacerbations. There are several patterns, of which plaque psoriasis is the most common. Guttate psoriasis, with raindrop shaped lesions scattered on the trunk and limbs, is the most frequent form in children, while pustular psoriasis is usually localized to the palms and soles. The classical inflammatory lesions vary from discrete erythematous papules and plaques covered with silvery scales, to scaly itching patches that bleed when the scales are removed. Despite a voluminous scientific literature and numerous treatment strategies, there is still no effective treatment for psoriasis that is completely without side effects.
The number of different and sometimes toxic treatments employed for amelioration of psoriasis is testimony to the resistant nature of this disease. Not only is moderate to severe psoriasis resistant to topical treatments, but because of its chronic and recurrent nature, systemic therapy or radiation is often required. The devastating nature of this disease is emphasized by the extent of the side effects that psoriasis sufferers are willing to endure to attain a remission to a disease that they know will recur sooner or later.